The present invention relates to distance measuring devices.
One of such devices is disclosed for example in the German patent document DE-A-43 16 348. It is used for different measuring operations. For example, the measuring device can be used for frequently needed applications to measure from an inner surface, for example an inner wall, bottom, or cover at a rear side, or in other words with an abutment surface which faces away from the object and abuts against a reference surface. For this case, where measurements must be performed starting from an outer edge, the known distance measuring device can abut in direction toward the object to be measured at its front surface, or in other words, with an abutment surface facing the object, against the reference surface. Depending on the application, as a device-side reference or zero point of the distance measurements is determined the front side or the rear side of the distance measuring device is determined. This however has a disadvantage that the operator must introduce the selected abutment type so as to take into consideration the associated reference point during the measurements. When an error occurs in this introduction or the introduction is forgotten, false measurement results can be obtained.